Early topics:
Two of the most important characteristics of good design are discoverability and understanding
"We must design our machines on the assumption that people will make errors."
Affordance vs Signifiers:
Mapping: When the mapping uses spatial correspondence between the layout of the controls and the devices being controlled, it is easy to determine how to use them
Feedback
Conceptual Models
Definition: The system image is what can be derived from the physical structure that has been built (including documentation).
Goals:
Psychological Variables Differ From Physical Variables: In many situations, the variables easily controlled are not those that the user cares about.
MacKenzie, I.S. (2013). Chapter 4: Scientific Foundations. Human-Computer Interaction: An Empirical Research Perspective. (pp. 121-152). Waltham, MA: Elsevier.
3 definitions:
Additional characteristics of research:
Research versus engineering versus design
Definitions:
How are observations made:
Measurement scales:
What: Conduct experimental research to answer (and raise) questions about a new or existing user interface or interaction technique.
Difficulty: People exhibit variable behavior, which affects confidence in our findings.
Questions:
Definition: Accuracy of answer (internal) vs breadth of question (external)
Tradeoffs:
Ecological validity vs external validity:
Takeaway: "A comparative evaluation yields more valuable and insightful results than a single-interface evaluation"
Causal relationship: "condition manipulated in the experiment caused the changes in the human responses that were observed and measured"
Finding a topic:
Müller, H., Sedley, A., & Ferrall-Nunge, E. (2014). Survey research in HCI. In J. Olson & W. Kellogg (Eds.) Ways of Knowing in HCI (pp. 229-266). New York: Springer.
Common biases: Satisficing - Respondents use suboptimal amount of effort.
- Respondents are more likely to satisfice when (Krosnick, 1991):
- Cognitive ability to answer is low.
- Motivation to answer is low.
- Question difficulty is high at one of the four stages, resulting in cognitive exertion.
- Avoid by:
- Keeping answers concise
- Avoid using same rating scale in series
- Avoid long surveys
- Explain importance of survey
- Avoid trap questions (e.g. "enter 5 in the following box")
Acquiescence Bias - Respondents want to please the surveyer.
- Avoid by:
1. Using agree/disagree, yes/no, true/false answers
2. Ask Qs about the underlying construct (?)
3. Use reverse-keyed constructs (asking same construct both positive and negative).
Social Desirability - respondents answer questions in a manner they feel will be positively perceived by others
- Avoid by allowing anonymous answers.
Response Orer Bias - tendency to select the items toward the beginning or the end of an answer or scale.
Question Order Bias - Each question in a survey has the potential to bias each subsequent question by priming respondents
Cognitive Pretesting - take the survey while using the think-aloud protocol (similar to a usability study).
Field Testing - Piloting the survey with a small subset of the sample
Monitoring Survey Paradata
Maximizing response rates: "Total Design Method":
One strategy to maximize the benefit of incentives is to offer a small non-contingent award to all invitees, followed by a larger contingent award to initial non-respondents (Lavrakas, 2011).
Cleaning:
Assessment:
Hypothesis testing - probability of a hypothesis being true when comparing groups (using t-test, ANOVA, Chi-square)
Inferential statistics can also be applied to identify connections among variables:
Analysing Open-ended Responses: